It is well known to provide seepage resistant structures using water-swellable clays, such as bentonite, disposed across a path of possible seepage or flow and confining the clay within an article of manufacture installed in an area of possible seepage. For example, this assignee's Bechtner U.S. Pat. No. 2,277,286 discloses the use of bentonite clay filled between spaced forms or bulkheads, such as wood, masonry or other suitable materials to hold the bentonite in place. Another of this assignee's prior patents to Arthur G. Clem, U. S. Pat. No. 3,186,896 discloses a moisture-impervious panel preformed from spaced paperboard sheets interconnected with an intermediate layer of water-swellable clay, such as bentonite, that has been sold for may years by this assignee as a waterproofing barrier. When subjected to leakage or seepage of water, the outwardly extending water-pervious paper or cardboard facing sheet will absorb the water and pass the water through the facing sheet for contact with the intermediate layer of water-swellable clay thereby permitting the clay to hydrate, swell and block the passage of water completely through the panel. As set forth in the Clem U.S. Pat. No. 3,186,896, the facing sheets should have no openings which permit the escape of the compacted bentonite therethrough.
Further, various polymers, swellable clays, and articles of manufacture have been applied to the surface of soil to provide a waterproofing layer to prevent the penetration of water and hazardous or toxic materials into the earth, and to provide lagoons, ponds and other water containment areas. Water-swellable clays, such as bentonite, have been applied directly to the soil surface and impacted in place, as disclosed in this assignee's prior U.S. Pat. No. 3,986,365. In addition, many different multi-layered articles of manufacture containing a water-swellable clay, such as bentonite, have been manufactured by adhesively securing the water-swellable clay to major interior surfaces of flexible sheet materials for application to the soil surface in abutting or overlapping relation of adjoining multi-layered articles. Examples of flexible sheet materials containing adhesively secured water-swellable clays are found in the following U.S. Pat. Nos. Clem 4,467,015; Clem 4,501,788; McGroarty et al 4,693,923; Harriett 4,656,062; and Harriett 4,787,780.
U.K. published patent application GB 2,202,185A discloses a layer of water-swellable bentonite between flexible layers that have been needle punched together in a needle loom that secures material from a lower layer of non-woven textile material to an upper layer of non-woven textile material, and secures material from an upper non-woven textile material to the lower non-woven textile material.
Another water proofing barrier, disclosed in Blias U.S. Pat. No. 4,344,722, is constructed in the field by applying a first flexible, water-permeable fabric layer, overlaying a thickness of water-swellable clay material and applying an overlayer of the same flexible, water-permeable fabric thereover. Other patents disclosing the use of water-impermeable layers for protecting a soil surface include British Patent Specification 1,059,363; British Patent Specification 1,029,513 and British Patent Specification 1,129,840.
Other prior art patents, for example Clem U.S. Pat. No. 4,501,788 and the McGroarty U.S. Pat. No. 4,693,923, disclose multi-layered flexible articles containing a water-swellable clay and having overlap areas containing no clay so that one sheet of the multi-layer article can be overlapped over an adjacent article on the area that is void of clay.
Problems prevalent with the use of the moisture-impervious panels disclosed in the Clem U.S. Pat. Nos. 3,186,896 and 4,501,788 and the McGroarty U.S. Pat. No. 4,693,923, are that 1) overlapping paper or cardboard facing sheets used to form the exterior surfaces of these panels require a period of time in order to become saturated sufficiently to permit water to penetrate the sheet and contact the intermediate water-swellable clay layer, and 2) the water-swellable clay is imperfectly abutted together at the seam so that water can penetrate through the panels at the seam areas. During this facing sheet saturation period, and initial multi-layer article water contact period, water in contact with the panels flows laterally over the facing sheet and can find a seam, crack, crevice or panel-damage area so that water can penetrate the panel, or penetrate between adjacent panels, at one or more locations before the intermediate water-swellable clay layer has had sufficient time to hydrate sufficiently and swell laterally to prevent this water penetration. Though such water damage will probably be of a relatively minor consequence, caused during a relatively short period of time until the intermediate water-swellable clay layer has had sufficient water contact for hydration, with repeated leakage, such water damage can be substantial and can create damage areas capable of substantial water penetration over time, in addition to being very costly to excavate and repair. Although this problem has existed since the first use of these water-impervious panels, for over twenty years, presenting a long-felt need in this art, to date this problem has not been solved.
Many attempts have been made to improve upon the water-impermeability of multi-layer articles of manufacture containing bentonite. The following patents represent efforts to provide a water-impervious sheet material containing adhesively secured water-swellable clays: Clem U.S. Pat. No. 4,467,015; Clem U.S. Pat. No. 4,501,788; McGroarty et al U.S. Pat. No. 4,693,923; Harriett U.S. Pat. No. 4,656,062; and Harriett U.S. Pat. No. 4,787,780. Other patents disclose the use of water-impermeable layers for protecting a soil surface, such as British patent specification 1,059,363; British patent specification 1,129,513 and British patent specification 1,129,840. Blias U.S. Pat. No. 4,344,722 discloses a water barrier constructed in the field by applying a first flexible, water-permeable fabric layer to a soil surface, overlaying a thickness of water-swellable clay material, and applying an overlayer of the same flexible, water-permeable fabric thereover. This eliminates the need for applying an adhesive to secure the clay to fabric sheets, but is expensive since the barrier material cannot be preformed but must be constructed in the field. U.K. published patent application GB 2,202,185A discloses a layer of water-swellable bentonite between flexible layers that have been needle punched together in a needle loom.
The following two patents disclose envelopes of water-absorbent polyacrylates that degrade in the liquid being absorbed to immobilize the liquid: Cullen U.S. Pat. No. 4,748,069 and Cullen et al U.S. Pat. No. 4,749,600. Agro et al U.S. Pat. No. 3,561,177 discloses a bentonite caulking rope enclosed in a water-soluble material, but neither discloses nor suggests its use at multi-layer article seam areas.
The above-described problems inherent with attempting to fit together adjacent water sealing articles in order to prevent water from leaking through the joints or seams are overcome in accordance with the principles of the present invention by providing a elongate, flexible confined mass of the water-swellable clay for positioning between, under or over adjacent sheets of water-barrier material manufactured in such a way that the elongate, confined mass of water-swellable clay will hydrate to prevent water from penetrating the seam or joint area.